# Bolt - plate contact

**URL:** <https://prepomax.discourse.group/t/bolt-plate-contact/3315>\
**Category:** General Questions\
**Tags:** results\
**Created:** [March 6, 2026, 10:02am UTC](https://prepomax.discourse.group/t/bolt-plate-contact/3315 "2026-03-06T10:02:35Z")\
**Posts on this page:** 1\
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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [March 6, 2026, 10:21am UTC](https://prepomax.discourse.group/t/bolt-plate-contact/3315/2 "2026-03-06T10:21:11Z")

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> [@fasanifrancesco](#):
>
> The errors span from Jacobian matrix errors ,when I try to simulate the contact between head bolts and plate with “Tie contact”, to non convergence when I simulate the contact with friction. Do you have any tips to try to get out of my condition?

Negative jacobian with tie constraints means that you should disable Adjust for them. Convergence is much more tricky and can have many causes (although it usually originates from contact). To find them, it’s best to simplify the model (reduce its size e.g. to segment with one bolt and gradually disable some advanced features such as the 3 nonlinearities).

At the first glance, it seems that you could utilize symmetry in one plane. Also, you should improve the mesh - refine it for shells and use hexa or at least second-order tetra elements for the bolts. You will find many examples of similar models on the forum if you search for solid bolts. Such as this thread: [COMPRESSION ONLY for simulating bolts and nut faces](https://prepomax.discourse.group/t/compression-only-for-simulating-bolts-and-nut-faces/3110) Or this one: [Error during analysis of baseplate fixing](https://prepomax.discourse.group/t/error-during-analysis-of-baseplate-fixing/1471)

Displacement-based preloading is much better for convergence.

In the second step, where you apply the actual loading, you should freeze the preload (Displacement → Fixed).

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